Indicating control means for variable electrical components



April 1 1931- s. E. CONDLIFFE 1,800,210

INDICATING CONTROL MEANS FOR VARIABLE ELECTRICAL COMPONENTS Filed Jan. 23,1951 2 Sheets-Sheet 1 Winn INVENTOR.

\ George E.Condliff,

April 1.4, 193 s. E. CONDLIFFE 1,800,210

INDICATING CONTROL MEANS FOR VARIABLE ELECTRICAL COMPONENTS Filed Jan. 25, 1931 2 Sheets-Sheet 2 I N VEN TOR.

5 G e Orge ECondl if f e,

Patented Apr. 14, 1931 A UNITED STATES PATENT, OFFICE GEORGE EDWARD CONDLIFFE, OI GERBADS CROSS, ENGLAND, ASSIGNOR TO VICTOP TALKING MACHINE COMPANY, A CORPORATION OF NEW JERSEY INDICATING CONTROL MEANS FOR VARIABLE ELECTRICAL COMPONENTS Application filed January 23, 1931, Serial No. 510,836, and in Great Britain January 17, 1980.

of the means for indicating the amount of variation given to the tuning device, which arrangement is the most effective for ensuring ease of control, another arrangement which provides the greatest efliciency of operation, and still. another arrangement.

which'is an improvement from the point of view of appearance.

While it is desirable that the variable com-- ponent and the indicating means should be arranged so as to ensure that all these advantages may be obtained, inherent mechani cal limitations often interfere therewith, and at best heretofore have often entailed the employment of complicated mechanical linkages between the variable component or tunifng device and the indicating means there- Among other things it is desirable to be able to provide a predetermined ratio between the movement of the indicating means and the movement of the variable component, for thereason that direct indication of the movement or position of adjustment of the component is usually not an accurate indication of its adjusted value or the operatin condition in the apparatus efiected by t e position of adjustment towhich it'is moved, such as the tuning adjustment of radio apparatus controlled by the variable com onent. Accurate com ensating or correctlve control of the ratio between the comonent or apparatus controlled and the incating means therefor, is diflicult' to provide by simple and easily operable' linkages of a mechanical nature between the component and the indicating means."

Accordingly it is an ob ect of the present invention to provide an improved indicatand control-means which includes a' in lirfirage between the variable component and the indicating means, of a type adapted The invention will be described, by way of example, and will be better understood with reference to the accompanying drawings, which show the invention as applied to the tuning control shaft of radio receiv-.

ing apparatus, and its scope will be pointed out in the appended claims.

In the drawing, Fig. 1 is a plan view, partly in section, of an indicating'control means embodying the invention; Fig. 2 is a-view-in elevation, also partly in section, of the indicating control means of Fig. 1, onthe same scale; and Fig. 3 is a view in perspective, on an enlarged scale, of a detail.

Referring to the drawings, 1 is a variaable electrical circuit component which, for example, may be a condenser or other tun in control means fora radio receiver, provi ed with and controlled by a rotary control shaft 2. Rotation of the shaft produces a corresponding rotation of a 'cam 3 which is mounted on the shaft coaxially therewith. f

A- lever 4 co-operates with the cam and is held'in engagement therewith by a suitable spring 5.

The lever 4 carries. a mirror 6' which is illuminated by means of a lamp 7 having a hood or cover 9 provided with a light projecting orifice or opening 10 through which it pro ects a ray or beam of light 11 onto the mirror. The mirror bears an indicator in the form of an indicating mark 11 (Fig. 3) which is projected and moves between, and in the direction indicated by, lines 12-13 onto an indicating scale 8 of suitable translucent material. I

Rotation of the control shaft 2 in tuning or operating the variable component 1 pro- 5 duces a corresponding deflection of the indicating mark 11 on the scale between lines 12-13 and causes the image of the mark or indicator to sweep across the scale.

Since the scale is translucent, the, indicator 19 mark appears to move and lie in the scale. The position of the scale can be chosen to the best advantage, the indicating beam being reflected thereon by a suitable disposition of the mirror. In the present example,

15 the scale is mounted in a suitable support or panel 14, preferably of opaque material, carried by a common base 15 of the appara'- tus along with a bracket 16 for the lamp and a support 17 for the lever. The lever 20 turns on a fixed pivot 18 carried by the supsingle light source, however, serves thus to illuminate the scale and provide the indication.

It is relatively-easy to provide any desired valuein the ratio of the movement of the beam of light to the movement of the oper-.

ating knob, as this depends upon the dimensions of the lever or the design of the cam 4% surface. Thus, any desired scale length can be used, and by providing a cam having the desired shape, any desired relationship between the value of the component 1 or tuning of the apparatus and the scale deflection may be employed." For example it will be seen that should the scale indication desired at the scale 8 not agree with the position of the variable component 1 to indicate its value or the condition. of the apparatus correspondin thereto, the shape of the; cam may be ma e to correct therefor and to hold the lever for any position of adjustment of the component l in -suchposition 5 that the image of the indicator will be pro- -rect point. v The simplified tuning control and indicating means 'provided is thus particularly adapted for use with radio apparatus reuiring accurate indication and control of time tuning components and because. of its simple'construction is adapted to easily be applied thereto.

it is obvious that the'embodimen't shown and described by way of example, may be 5 ,jected onto thescale at the desired or cormodified to suit difierent operating condi-, tions and the physical arrangement of the apparatus employed. The simple cam controlled mirror and distant scale connected by a beam of light including an indicating image provides an accurate indication of the value of the variable component or the condition of the apparatus controlled thereby. It will be noted that this arrangement thus provides simultaneous indication and illumination from the same light source.

I claim'as my invention 1. In combination, a variable electrica circuit component having an operating con trol shaft, a cam arranged to be moved by said shaft, a scale, an indicator for the scale, and means actuated by said cam and including a movable mirror, for projecting an image of said indicator upon said scale.

2. In .a radio apparatus, the combination with a variable circuit component having a control shaft, of means for indicating a characteristic of the apparatus responsive to variations of said circuitcomponent, said means including a movable mirror, an indicator carried by the mirror, a cam carried by the shaft and arranged to move said mirror in response to movement of said shaft, a light source for projecting'a beam of light upon the mirror and indicator, and a scale arranged inspaced relation to the mirror to intercept the projected beam of light and the image of said indicator-from said mirror.

v3. In a radio apparatus, the combination with a variable circuit component having a control shaft, 'of means for indicating a characteristic of the apparatus responsive to variations of said circuit component, said means including a movable mirror, an'indicator carried by the mirror, a cam carried by the shaft and arranged to move the mirror in response to movement of said shaft, 2. light source for projecting a beam of light upon the mirror and indicator, and a scale. arranged in spaced relation to the mirror -to intercept the projected beam of light and the image of said indicator from said mirror, said scale and light source be: ing arranged to lie in different planes with respect to each other and a plane normal to the mirror.

4. In combination, a variable electrical circuit component having an operating shaft, a movable mirror, an indicator carried by the mirror, means for moving said mirror in response to movement of said shaft in accordance with variations in the electrical circuit value of said. component a scale arranged .in spaced relation to said mirror, toreceive therefrom a beam of light and an image of said indicator, and a light source arranged to project said beam of light upon said mirror thereby indirectly to i1- luminate said scale and to provide said image of said indicator.

5. In a radio apparatus, the combination with a variable electrical circuit component havin a control shaft,of means adaptedto A provi e a beam of light, means IBSPODSIVO to movement of said control shaft for altering the direction of said beam of light in accordance with variations produced inthe electrical circuit value of said electrical component, said means including a movable mirror an indicator on said mirror wherecontrol means therefor, including a contro shaft, an indicating scale, a source of light, a mirror arranged to project a beam of light from said source onto said scale, said mirror being provided with an indicating mark whereby the image of said mark appears on said scale whensaid mirror is illuminated by the light source,.and a cam connected with said control shaft and arranged to move said mirror in nse to movement of the control shaft, sai cam being shaped to cause said mirror to move in apredetermined manner.

In testimony whereof I have hereunto subscribed my name this sixth day of January,

GEORGE CONDLIFFE.

an operating 

